(19)
(11) EP 1 650 857 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.05.2007 Bulletin 2007/20

(43) Date of publication A2:
26.04.2006 Bulletin 2006/17

(21) Application number: 05109431.6

(22) Date of filing: 11.10.2005
(51) International Patent Classification (IPC): 
G05F 1/70(2006.01)
H02M 1/00(2007.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL BA HR MK YU

(30) Priority: 21.10.2004 IT MI20042004

(71) Applicant: STMicroelectronics S.r.l.
20041 Agrate Brianza (Milano) (IT)

(72) Inventors:
  • Adragna, Claudio
    20052, MONZA (MI) (IT)
  • Fagnani, Mauro
    20014, NERVIANO (MI) (IT)
  • Gattavari, Giuseppe
    21052, BUSTO ARSIZIO (VA) (IT)

(74) Representative: Mittler, Enrico et al
Mittler & C. s.r.l., Viale Lombardia, 20
20131 Milano
20131 Milano (IT)

   


(54) Device for the power factor correction in forced switching power supply units".


(57) The present invention describes is a device for power factor correction in forced switching power supply unit, comprising a converter (20) and a control device (100) coupled with the converter (20) so as to obtain from an input alternating mains voltage (Vin) a direct regulated voltage (Vout) on the output terminal. The converter (20) comprises a power transistor (M) and the control device (100) comprises an error amplifier (3) having in input on the inverting terminal a first signal (Vr) proportional to the regulated voltage (Vout) and on the non-inverting terminal a reference voltage (Vref), a drive circuit (4-7, 10) of the power transistor (M) coupled with the output terminal of the error amplifier (3). The control device (100) comprises means (42, Cff, 101, Rt, 102) suitable for generating a current signal (It) representative of the effective input voltage; said current signal (It) is in input on the inverting terminal of said error amplifier (3) to vary said regulated voltage (Vout) in reply to variations of the effective input voltage.







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